I am considering buying a J3 in the next couple of days, as from all the reading around it seems to be the best choice for me, but I have a couple of what may well be stupid questions about the SD card slot.

If you have multiple SD cards, with different content on, is it easy to swap between them, or does the device end up getting confused with tracks that are on an SD card not currently present?

I am kind of thinking that the reason that the device takes longer to scan the external memory on start up (as I have read on here) is for this reason that it can track its internal memory, but has no way of knowing if the current SD card is the same card that was present when switched off - and this behaviour makes it easy to swap between cards.

Also, would I be right in thinking that you can't "hot swap" the cards while the device is in use?